The present invention concerns an acoustic monitoring device usable in a system for sound sensing, in the spatial codification or "Holophonic" recording, reproduction or broadcasting of sounds, and to a process for forming such an acoustic monitoring device. More particularly, the present invention concerns a device, and a process for forming the device, which device allows sound sensing in the recording, reproduction or transmission of acoustic perceptions in a manner giving listeners an effective spatial and true, total dimensional effect, rather than a merely bidimensional one.
Stereophonic recording has been done by placing two or more microphones in strategic points and recording sounds on a record or tape in two separate tracks. The sounds recorded on the two separate tracks are then reproduced through two strategically placed speakers. In another so-called "binaural" recording system, an object shaped like a human head is placed between two panoramic microphones, so as to artificially create an acoustic shadow to separate the two recorded stereo channels. Another existing device consists of an artificial head equipped with internal microphones. This device provides only a limited and imperfect stereophonic sound recording, and its full effect can only be appreciated by use of earphones or headphones because it uses physical delays and physiological delays created by differences in sound intensity between the two channels, or a shadowing effect. Still such device does not provide a Holophonic effect.
The present invention is the result of in-depth research and study and results from another interpretation of the way in which sound energy interacts with the human auditory system. Starting from this interpretation, the present invention provides a system which is able to give a true perception of the sound received. The invention can be considered to provide for the auditory system what laser holography provides for the visual system and thus can be considered holography of sound, or "Holophonics."
An examination of the hearing system shows that it must analyze information from various sound sources. In animals in general, the hearing system dynamically analyzes sound information by the sensorial effect of the entire body, as well as by spatial codification through the ears. In man, a highly evolved animal with a highly perfected hearing system, the hearing system performs an instantaneous static analysis of sound information, giving the position of the sound source with respect to the listener.
This human auditory system includes numerous features that contribute to the overall perception of sound received by a person. These anatomical features include the ears and their auricles and auditory meatus, the Eustachian tubes, and the nasal and oral cavities. In order to provide an acoustic monitoring device permitting accurate reproduction of auditory sensations, these anatomical features must be accurately reproduced. Hair is also of considerable importance in spatial discrimination, allowing a precise perception of sound coming from the front or the rear by giving rise to an asymmetric hologram. In fact, bald persons have been observed to have somewhat reduced front-rear discrimination along the axis of symmetry of the head.